IMTAN function text/scalc/01/func_imtan.xhp
IMTAN function tangent;complex number IMTAN function Returns the tangent of a complex number. The tangent of a complex number "a+bi" can be expressed by:
tan(a+bi)=sin(a+bi)/cos(a+bi) IMTAN(Complex_number) whose tangent is to be calculated.

=("4-3i") returns 0.00490825806749606-1.00070953606723i. =(2) returns -2.18503986326152 as a string.